function z=pso_func(in)
nn=size(in);
x=in(:,1);
y=in(:,2);
nx=nn(1);
   for i=1:nx
       temp=[x(i)^2-10*cos(2*pi*x(i))-10]*[y(i)^2-10*cos(2*pi*y(i))-10];
       z(i,:) = temp;
   end
